Genital herpes (herpes genitalis) is a disease caused by the herpes simplex virus. There are two types of herpes simplex virus (hereinafter "HSV"); type I and type II. HSV type II is generally associated with genital herpes. However, type I HSV has also been associated with genital herpes. The most common source of the HSV II infection is by venereal contact, although it may also be acquired during birth.
The disease is characterized by groups of watery blisters on mucous membranes. In males these lesions appear as ulcers on glans, prepuce and shaft of the penis. Herpes genitalis on the penis is extremely painful and the condition resolves on its own. In females, the disease is largely asymptomatic and may be characterized only by inflammation. A genital herpes infection may lead to other physiological complications such as urethritis, neuralgia or septic meningitis.
Infection with genital herpes often results in recurrent episodes involving the formation of blisters and sores associated with severe pain and itching. Recurrent HSV II infections are more common in older adults.
There is no known cure for herpes genitalis infections. Therefore, methods of treatment have been directed to treating the clinical manifestations of the disease. For example, topical anesthetics have been used to reduce the pain associated with the infection. Additionally, a method of preventing secondary infections has been employed designed to maintain the lesions in a dry state.
Acyclovir, 9-[(2-hydroxyethoxy)methyl]guanine, U.S. Pat. No. 4,199,574, marketed in the United States by Burroughs Wellcome under the trademark Zovirax.RTM., is an antiviral drug used in the treatment of herpes viruses. Acyclovir ointment is indicated in the management of initial herpes genitalis. Clinical trials of initial herpes genitalis with acyclovir ointment have decreased healing times and, in some cases, decreased the duration of viral shedding and pain, Physician's Desk Reference, 41st Ed., p. 814-818 (1987). However, acyclovir is apparently not useful for recurrent herpes.
It is an object of the present invention to provide both a method of treating episodes of genital herpes and a method useful in preventing recurrent episodes.